"We announce the official signing of free agent LB James Harrison. Mike Zimmer's defense just got a little bit nastier," the team announced on Twitter Tuesday morning, days after word of the deal first leaked last week.

“James has been a dominant player on a team with a history of dominant defense,” said Bengals head coach Marvin Lewis in a news release Tuesday. “He has made a great number of game-deciding plays, and he brings us help in a position area we had planned to improve either through the draft or with a veteran signing. He will be a physical player against the run and will improve our pressure on the quarterback.”

The five-time Pro Bowl player agreed to terms last Friday and signed the deal on Tuesday as the Bengals got ready for the draft. They've now got one position that's more secure.

"Great to get that done prior to the draft," coach Marvin Lewis said. "Gives us a sense of where we are, another part defensively. We all will be excited to have James join us."

The former Defensive Player of the Year was released by Pittsburgh after the two sides failed to agree on a reworked contract. The Steelers have to cut their payroll to get under the salary cap. Several teams were interested in Harrison, who was injured last year but finished the season strong.

The Bengals were impressed when he visited Cincinnati for a workout.

"He came in here and had a great visit and kind of bared his soul on things to us," Lewis said. "I think it showed really the kind of person he was for us. That was great. (He) worked on the field for us, which not a lot of guys at this point in his career would be willing to do that."

The 34-year-old linebacker helped the Steelers win two Super Bowls. He moves downriver to an AFC North rival that is trying to get past the first round of the playoffs. Cincinnati has made the postseason as a wild card team each of the last two years, losing to Houston both times.

The defense ranked sixth in the NFL in yards allowed last season and returns most of the unit intact. Linebacker was a main area of concern.

"With James, that was a big addition to us," Lewis said. "It kind of revved us from where we were a year ago, a step up from where we were a year ago in an area where I hoped to try to improve in some way or another. So we were able to do that."

Harrison missed time in training camp and the first three games last season with a knee injury, but finished with six sacks - tied for the team lead. The Steelers finished No. 1 in defense for the fourth time since Harrison became a starter in their 3-4 alignment.

Harrison helped the Steelers win the Super Bowl in 2006 and was the NFL's Defensive Player of the Year in 2008. He helped Pittsburgh win another Super Bowl that season by returning Kurt Warner's pass 100 yards for a touchdown at the end of the first half of a 27-23 victory.